Parabolic trough solar generation with underground cooling

ABSTRACT

A system, a thermoelectric generator, and a method for generating electricity are provided. The system includes a thermoelectric generator, a cooling system, and a heating system. The cooling system includes a cold side module configured to hold a predetermined volume of air, a subterranean heat exchanger including an underground conduit, the underground conduit having a first end configured to receive ambient air and a second end coupled to the inlet of the cold side module, and an air exhaust coupled to the outlet of the cold side module and having one or more valves configured to control an airflow from the subterranean heat exchanger towards the air exhaust. The heating system includes a first solar concentrator to collect light rays, a hot side module, and a fiber optic cable to transport the collected light rays to the hot side module.

BACKGROUND Field of the Invention

This invention generally relates to a thermoelectric generator system.In particular, the invention provides a thermoelectric generator systembased on renewable energy.

Background of the Invention

With ever increasing dependence on fossil fuels, interest in renewableenergy generation is increasing. Solar energy is harnessed using aplethora of technologies such as photovoltaic cells, solar thermalheating through parabolic reflectors or concentrators, solararchitecture, and artificial photosynthesis. Solar energy is one of thepromising techniques of renewable energy generation and it is mainlydivided into active and passive techniques depending on the means ofcapturing and distributing this energy. Active solar energy techniquesinclude semiconductor or organic photovoltaic technologies and solarconcentrators. Passive solar techniques include solar architecture(building orientation towards the sun), material selection that haveadequate thermal mass or light dispersing properties.

A thermoelectric generator (TEG) is a device that converts thermalenergy into electrical energy based on the Seebeck effect and thePeltier effect. The Seebeck effect or principle states that if two wiresof different materials are joined at their ends, forming two junctions,and one junction is held at a higher temperature than the otherjunction, a voltage difference arises between the two junctions. TheTEGs have many advantages such as no moving mechanical parts, longlifetime, quiet operation, and environmentally friendliness.

However, it has always been a challenging task to create a heat fluxbetween the two sides of the TEG. Accordingly, what is needed, asrecognized by the present inventor, is a method and system that createsthe heat flux using renewable energy.

The foregoing “Background” description is for the purpose of generallypresenting the context of the disclosure. Work of the inventor, to theextent it is described in this background section, as well as aspects ofthe description which may not otherwise qualify as prior art at the timeof filing, are neither expressly or impliedly admitted as prior artagainst the present invention.

Accordingly it is one object of the present disclosure to provide athermoelectric generating system that creates a heat flux for thethermoelectric generator using renewable energy.

SUMMARY

The present disclosure relates to a system for generating electricity.The system includes a thermoelectric generator, a cooling system, and aheating system. The cooling system includes a cold side moduleconfigured to hold a predetermined volume of air, a subterranean heatexchanger including an underground conduit, the underground conduithaving a first end configured to receive ambient air and a second endcoupled to the inlet of the cold side module, and an air exhaust coupledto the outlet of the cold side module and having one or more valvesconfigured to control an airflow from the subterranean heat exchangertowards the air exhaust. The heating system includes a first solarconcentrator to collect light rays, a hot side module, and a fiber opticcable to transport the collected light rays to the hot side module.

The present disclosure also relates to a method for generatingelectricity. The method includes heating a hot side of a thermoelectricgenerator via concentrated light rays collected using a solarconcentrator and transported via a fiber optic cable; cooling a coldside of the thermoelectric generator via a cooling system; andconnecting an output of the thermoelectric generator to a transformer toprovide AC current. The cooling system includes a cold side moduleconfigured to hold a predetermined volume of air, the cold side modulehaving an inlet and an outlet, a subterranean heat exchanger includingan underground conduit, the underground conduit having a first endconfigured to receive ambient air and a second end coupled to the inletof the cold side module, and an air exhaust coupled to the outlet of thecold side module and having one or more valves configured to control anairflow from the subterranean heat exchanger towards the air exhaust.

The foregoing paragraphs have been provided by way of generalintroduction, and are not intended to limit the scope of the followingclaims. The described embodiments, together with further advantages,will be best understood by reference to the following detaileddescription taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the disclosure and many of the attendantadvantages thereof will be readily obtained as the same becomes betterunderstood by reference to the following detailed description whenconsidered in connection with the accompanying drawings, wherein:

FIG. 1 is a schematic that shows a system for generating power using athermoelectric generator (TEG) according to one example;

FIG. 2 is a schematic that shows a cold air system according to oneexample;

FIG. 3 is a schematic that shows a heating system according to oneexample;

FIG. 4 is a schematic that shows a heat generator according to oneexample;

FIG. 5 is a schematic that shows a heat generator according to anotherexample;

FIG. 6 is a schematic that shows an illustration of the system accordingto one example;

FIG. 7 is a schematic that shows a system including a plurality ofthermoelectric generators according to one example;

FIG. 8 is a flowchart for a method for generating power using thethermoelectric generator according to one example; and

FIG. 9 is a schematic that shows a system for generating energy from aplurality of thermoelectric generators according to one example.

DETAILED DESCRIPTION

The terms “a” or “an”, as used herein, are defined as one or more thanone. The term “plurality”, as used herein, is defined as two or morethan two. The term “another”, as used herein, is defined as at least asecond or more. The terms “including” and/or “having”, as used herein,are defined as comprising (i.e., open language). The term “coupled”, asused herein, is defined as connected, although not necessarily directly,and not necessarily mechanically.

Reference throughout this document to “one embodiment”, “certainembodiments”, “an embodiment”, “an implementation”, “an example” orsimilar terms means that a particular feature, structure, orcharacteristic described in connection with the embodiment is includedin at least one embodiment of the present disclosure. Thus, theappearances of such phrases or in various places throughout thisspecification are not necessarily all referring to the same embodiment.Furthermore, the particular features, structures, or characteristics maybe combined in any suitable manner in one or more embodiments withoutlimitation.

The term “or” as used herein is to be interpreted as an inclusive ormeaning any one or any combination. Therefore, “A, B or C” means “any ofthe following: A; B; C; A and B; A and C; B and C; A, B and C”. Anexception to this definition will occur only when a combination ofelements, functions, steps or acts are in some way inherently mutuallyexclusive.

Referring now to the drawings, wherein like reference numerals designateidentical or corresponding parts throughout several views, the followingdescription relates to a system and associated methodology forelectrical energy generation via a thermoelectric generator (TEG).

The renewable electricity generation system described herein usesrenewable resources to provide a temperature difference to thethermoelectric generator. For example, the system uses naturalconvection and solar thermal energy collected via fiber optics bundles.

FIG. 1 is a schematic that shows a system 100 for generating power usinga thermoelectric generator 102 (i.e., a Seebeck generator) according toone example. The TEG 102 is a solid state device that converts heat flux(i.e., temperature differences) directly into electrical energy througha phenomenon called the Seebeck effect (a form of thermoelectriceffect). The generated electrical energy is proportional to thetemperature differences.

The thermoelectric generator 102 includes a first thermoelectric layerand a second thermoelectric layer. The first thermoelectric layer isdisposed adjacent to the second thermoelectric layer in a substantiallyparallel spatial relationship. The thermoelectric generator 102generates electrical energy as a function of a temperature differencebetween the first thermoelectric layer and the second thermoelectriclayer based on the Seebeck effect as described previously herein (alsoreferred to herein as the cold side and hot side of the TEG 102).

The system 100 creates a temperature differential across the TEG 102 viaa cooling system 104 and a heating system 106 (e.g., heat exchangers).The cooling system 104 and the heating system 106 supply cooling andheating to the cold side and hot side of the TEG 102, respectively. Thecooling system 104 is operatively connected to the cold side of thethermoelectric generator (e.g., the first thermoelectric layer) to coolthe cold side. The cold side of the TEG 102 is maintained at a constanttemperature in the range of 5 to 10° C. In one implementation, thetemperature is maintained using cool air cooled via a subterranean aircooling module as shown and described in FIG. 2. The cooling system 104may be coupled to multiple TEGs 102. The heating system 106 may also becoupled to the multiple TEGs 102. The TEG 102 may be an array of one ormore TEGs 102 arranged in a single layer between the cooling system 104and the heating system 106. The one or more TEGs 102 may be connected asa group to provide a specified voltage and/or current.

FIG. 2 is a schematic that shows the cooling system 104 according to oneexample. The cooling system 104 includes a subterranean air coolingmodule 202, a cold side module 204, and a first air exhaust 206. Air atambient temperature is input to the subterranean air cooling module 202.The air passes through the subterranean air cooling module 202 andreaches a predetermined temperature (e.g., temperature between 5 to 10°C.). The higher temperature at the first air exhaust 206 creates anatural air flow towards the cold side module 204.

The cold side module 204 is disposed adjacent to the firstthermoelectric layer (cold side of the TEG 102) and hold a predeterminedvolume of air. The cold side module 204 maintains the firstthermoelectric layer at a cold temperature with respect to the secondthermoelectric layer via the flow of cold air from the subterraneancooling module 202 towards the first air exhaust 206. The cold sidemodule 204 includes at least one inlet and one outlet. The inlet iscoupled to the subterranean air cooling module via a conduit. Theconduit is insulated to minimize heat exchange with ambient air. Thecold side module 204 may be coupled to multiple subterranean air coolingmodules.

The first air exhaust 206 includes an inlet and an outlet. The inlet iscoupled to the outlet of the cold side module 204 via a conduit. Theoutlet includes one or more valves to control the output of the air. Thefirst air exhaust 206 may be an air tank that holds a predeterminedvolume of air. The first air exhaust 206 may be heated via light rays orvia ambient air to maintain a hotter temperature with respect to the airin the cold side module 204. The first air exhaust may also include afan to withdraw air from the cold side module 204. Alternatively, thefan may be disposed on a side of the cold side module 204 to withdrawthe air.

The cold side module 204 has a rectangular shape. At least one side ofthe cold side module 204 is in a direct contact with the cold side ofthe TEG 102. In one implementation, the at least one side of the coldside module 204 has a size and a shape that match the size and the shapeof the cold side of the TEG 102.

In one implementation, multiple TEGs 102 are disposed in direct contactwith the at least one side of the cold side module 204 to cover thecomplete surface of the at least one side of the cold side module 204.The cold side module 204 may include insulating materials to minimizeheat exchange with the ambient air. For example, one or more layers ofinsulating materials may be disposed on the side of the cold side modulenon-adjacent to the first thermoelectric layer (or cold side). In oneexample, insulating materials are disposed on inside or outside surfacesof the cold side module 204 that are not in direct contact with the coldside of the TEG 102. Insulating materials may also be disposed on thehot side of the TEG 102. Insulating materials may includenon-electrically conductive materials that withstand high temperatures.High-temperature examples of insulation include ceramics in both solidand fabric form, as well as other inorganic thermal insulators.Additionally, for lower-temperature operations, various polymers can beused. Suitable examples of such polymers include neoprene and/orsilicone rubber. The cold side module 204 may be of size and shapecorresponding to the size and shape of the cold side of thethermoelectric generator 102 as described previously herein.

The subterranean air cooling module 202 may include a conduit disposedunderground and coupled to the cold side module 204. The subterraneanair cooling module 202 may include a fan to induce air to the conduit.The fan may be coupled to a first end (or inlet) of the conduit. As airmoves through the underground conduit the earth or ground acts as a heatexchanger to cool the air passing through the conduit. The cooled air isdirected from the underground conduit into the cold side module 204 soto cool the cold side of the TEG 102. The underground conduit has ashape/size to maximize heat transfer with the soil or geologicalformation. For example, the underground conduit includes multiple finson an outer surface of the underground conduit to enhance heat exchangewith the soil. An insulation layer may be disposed on outer surfaces ofthe conduit that are above ground level. Insulation layers may be aroundthe entire length of the underground conduit. The layers may include amoisture retaining layer (e.g., a layer of sand disposed in between twoother insulation materials). The moisture retaining layer helps increasethe efficiency of heat exchange with the underground conduit. The layerstype and thickness are selected based on the characteristics of theground at the location of the system 100.

In one implementation, the subterranean air cooling module includes 202a metal pipe located 5 to 5 feet beneath the ground where thetemperature is approximately constant at 5 to 10° C. (constanttemperature depth zone). The location of the metal pipe beneath theground may be based on the characteristics of the ground at the locationof the system 100 (i.e., based on the type of soil). Further, the lengthand shape of the metal pipe may be based on the characteristics of theground and desired temperature of air.

The underground conduit may include multiple sections of differentdiameters. For example, a first section of the underground conduitincludes a vertical stretch from the inlet to a predetermined depthassociated with the constant temperature depth zone. A second sectionincludes a horizontal stretch at the predetermined depth. A thirdsection includes a vertical stretch from the predetermined depth to theinlet of the cold side module 204. The first section and the thirdsection may be substantially straight stretches. The second section mayhave a serpentine shape (in the horizontal plane). An end of the firstsection is coupled to a first end of the second section via a firstelbow. A second end of the second section is coupled to an end of thethird section via a second elbow.

In one implementation, the second section includes two or more parallelstretches. The stretches are coupled together at the first elbow and thesecond elbow. A diameter of the conduit at the second section may belarger than the diameter of conduit in the first section. The diameterof the conduit in the third section is equal to the diameter of theconduit in the first section. The first elbow and the second elbow are90 degree elbows. A first end of the first elbow has a diametercorresponding to the diameter of the conduit in the first section and asecond of the first elbow has a diameter corresponding to the diameterof the conduit in the second section. The change in diameter providesgreater control on the flow of air in the subterranean air coolingmodule 202.

FIG. 3 is a schematic that shows the heating system 106 according to oneexample. The heating system 106 includes a heat generator 306, a secondair exhaust 302, and a hot side module 304. The heat generator 306 mayinclude a solar thermal concentrator or a black body system toconcentrate solar radiation to generate heat for the hot side of the TEG102 as discussed further below. The hot side module 304 maintains thesecond thermoelectric layer at a higher temperature relative to thefirst thermoelectric layer. The hot side module 304 may includeinsulating materials disposed on the side non-adjacent to the secondthermoelectric layer to minimize the loss of heat due to the ambienttemperature (e.g., heat exchange with the ambient air). In one example,the hot side module 304 may be in a direct contact with the hot side ofthe TEG 102. In another example, a material may be deposited between thehot side module 304 and the hot side of the TEG 102 such as a heatretaining material.

The heat generator 306 may include one or more fans to circulate theheated air towards the hot side module 304. In one implementation,natural convection heat transfer mechanism is used to transfer heatusing air flow.

Air and/or fiber optics bundles (FOB) are used to carry heat orconcentrated solar light rays to the hot side of the TEG 102. Thetemperature of the generated heat depends on weather conditions, time ofthe year, time of the day, and the like. The hot side module 304includes insulating materials and heat retaining materials as discussedpreviously herein. The hot side module 304 may be of a size and shapecorresponding to the hot side of the TEG 102. The heat generator 306 mayprovide heat to multiple TEGs 102.

FIG. 4 is a schematic that shows the heat generator 306 according to oneexample. The heat generator 306 includes a solar concentrator 402 and anoptical fiber bundle 404. The solar concentrator 402 may include one ormore optical elements (e.g., lenses, mirrors) configured to focusincident light rays from the sun to an entry of an optical fiber and/ora bundle of optical fibers. The optical fiber bundle 404 carries theconcentrated light to the hot side module 304. The fiber optics may becomposed of plastic fiber optics (e.g., Polymethyl methacrylate (PMMA)and fluorinated polymers). In one implementation, the fiber optics maycarry to one or more thermoelectric generators as discussed furtherbelow. The solar concentrator 402 may include a Fresnel lens whichfocuses light and infrared radiation from the sun onto a solar radiationcollector or a collector plate of the solar concentrator 402. The solarconcentrator 402 may be rotatable in order to maximize power generation.For example, the solar concentrator 402 may be oriented with the sun tomaintain proper focus.

In one implementation, the solar concentrator 402 is a Fresnel lens. Thefiber optic bundle terminates to provide a surface that coincides withthe focal point of the Fresnel lens. The fiber optic bundle can be cutso it has an angled terminus (a terminus that ends in a 45° angle) andthe Fresnel lens is focused on the exposed ends of the cable.

In one implementation, the fiber optic bundle is mounted on a stage tomaximize the coupling efficiency of the focused lights from the Fresnellens. The fiber optic bundle may couple light from the ultraviolet (UV)and infrared (IR) spectra to maximize the heating.

The concentrated light rays heat the air in the hot side module 304. Inone implementation, the concentrated light rays may heat directly thesecond thermoelectric layer and/or the hot side module 304 as shown inFIG. 5.

FIG. 5 is a schematic that shows the heat generator 306 according toanother example. The heat generator 306 includes a heat concentrator510, a hot air tank 502, and a third air exhaust 508. The hot air tank502 is coupled to the hot side module 304 via a first air conduit 504.The hot side module 304 is coupled to the third air exhaust 508 via asecond air conduit 506.

The heat concentrator 510 may include a solar concentrator that focuslight and infrared radiation on the hot air tank 502 to heat the air.The solar concentrator includes two or more solar concentrators thatfocus light on multiple locations of the hot air tank 502. Each of thesolar concentrators may include multiple parabolic units configured tofocus light on one location of the multiple locations. The two or moresolar concentrators are mounted on a controlled stage to track the sunto maximize efficiency.

In addition or alternatively, air may be heated in an insulated conduitusing the heat concentrator 510. The insulated conduit may be positionedalong the focal location (e.g., focal axis) of each parabolic unit ofthe solar concentrator. In other words, multiple heat concentrators arepositioned so as the insulated conduit is in the direct path of thereflected solar light rays. A first end of the insulated conduit iscoupled to the hot side module 304. A second end of the insulatedconduit is coupled to the hot air tank 502. Thus, air in the insulatedconduit get heated and flow towards the hot side module 304.

In one example, the hot side module 304 and the cold side module 204 mayinclude compressed air to facilitate heat exchange. The subterranean aircooling module 202 may receive compressed air from an air compressor ora compressed air storage tank. Further, the hot air tank 502 may befilled with compressed air. The third exhaust 508 may be coupled to thehot air tank 502 to recycle air in the system.

FIG. 6 is a schematic 600 that shows an illustration of the systemaccording to one example. The TEG 606 includes a cold side 612 and a hotside 614. A cold side module 608 is disposed in a parallel fashion withrespect to the cold side 612. The cold side module 608 may be in adirect contact with the TEG 606. A hot side module 610 is disposed in aparallel fashion with respect to the hot side 614 of the TEG 606. Thehot side module 610 may be in a direct contact with the TEG 606. Hot airto the hot side module 610 is heated using solar energy. The light raysare directed to the hot side module 610 using fiber optics 628 from asolar concentrator 626. In addition, solar energy is used to heat a hotair tank 622. The hot air tank 622 has an input to receive air atambient temperature. The air is heated in the hot air tank 622 anddirected to the hot side module 610 via conduit 620. The hot side module610 is connected to a third air exhaust 616 via conduit 618. Theconcentration of air at the third air exhaust 616 creates a natural flowfrom the hot air tank 622 towards the hot side module 610 then towardsthe third air exhaust 616.

The cold side module 608 is coupled to a first air exhaust 602 viaconduit 624. Cold air is provided to the cold side module 608 via anunderground conduit 604. Air at ambient temperature is cooled whenpassed through the underground conduit 604. The first air exhaust 602may be heated by solar energy to create a natural air flow from theunderground conduit 604 towards the first air exhaust 602.

FIG. 7 is a schematic that shows a system 700 for generating energy froma plurality of thermoelectric generators according to one example. Inone implementation, the system 700 may include a first thermoelectricgenerator 102 a, a second thermoelectric generator 102 b, and a thirdthermoelectric generator 102 c. The system 700 may include a processor702 to control the operation of each of the first thermoelectricgenerator 102 a, the second thermoelectric generator 102 b, and thethird thermoelectric generator 102 c. The TEGs may be arranged in avertical fashion to minimize ground space usage. The processor 702 maycontrol one or more systems of the solar concentrator 402 associatedwith each of the first thermoelectric generator 102 a, the secondthermoelectric generator 102 b, and the third thermoelectric generator102 c. For example, the processor 702 may control the stage associatedwith each of the solar concentrator 402 to follow the sun to maximizeefficiency.

In one implementation, a solar concentrator may be coupled to two ormore thermoelectric generator system. For example, the fiber optics maycarry light rays to the first thermoelectric generator 102 a, the secondthermoelectric generator 102 b, and the third thermoelectric generator102 c from a single solar concentrator. A first end of the fiber opticsis coupled to the concentrator and a second end is coupled to a fiberoptic splitter. For example, a 1×3 equal ratio splitter may be used todivide the concentrated solar light rays into 3 beams, each representing⅓ of the concentrated solar light rays. Each beam is coupled to hot sidemodules associated with each of the first thermoelectric generator 102a, the second thermoelectric generator 102 b, and the thirdthermoelectric generator 102 c. A non-equal ratio splitter may be usedto direct a larger portion of the concentrated solar light rays towardsone of the thermoelectric generators. For example, 50% of theconcentrated light rays are directed to a first hot side module, 25% ofthe concentrated light rays are directed to a second hot side module,and 25% are directed to a third hot side module when the predeterminedvolume of air associated with the first hot side module is greater thanthe predetermined volume of air held in the second and the third hotside module.

FIG. 8 is a flowchart for a method 800 for generating power using thethermoelectric generator according to one example. At step S802, a hotside of a thermoelectric generator is heated via concentrated rays ofthe sun.

At step S804, a cold side of the thermoelectric generator is cooled viaair cooled via an underground conduit. The underground conduit ispositioned at a predetermined distance beneath ground.

At step S806, an output of the thermoelectric generator is connected toa transformer to provide a voltage based on the user requirements.

FIG. 9 is a schematic that shows a system 900 for generating energy froma plurality of thermoelectric generators according to one example. Thecold side module may provide cooling for two or more TEGs 102. Forexample, a first side of the cold side module 904 is in direct contactwith a cold side of a first TEG 902 a and a second side of the cold sidemodule 904 is in direct contact with the cold side of a second TEG 902b. In addition, as discussed previously herein, the first side of thecold side module 904 may provide cooling to multiple TEGs. In oneimplementation, an entire outer surface of the cold side module is incontact with cold sides of multiple TEGs. In one implementation, 25 TEGsmay be arranged in a single 5×5 matrix between the cold side module 204and the hot side module 304.

A system which includes the features in the foregoing descriptionprovides numerous advantages to users. In particular, the system ispractical, relatively inexpensive, durable, and easy to maintain. Thesystem described herein provides electricity for long period. The systemdescribed herein has low noise generation and does not include movingparts.

Obviously, numerous modifications and variations are possible in lightof the above teachings. It is therefore to be understood that within thescope of the appended claims, the invention may be practiced otherwisethan as specifically described herein.

Thus, the foregoing discussion discloses and describes merely exemplaryembodiments of the present invention. As will be understood by thoseskilled in the art, the present invention may be embodied in otherspecific forms without departing from the spirit or essentialcharacteristics thereof. Accordingly, the disclosure of the presentinvention is intended to be illustrative, but not limiting of the scopeof the invention, as well as other claims. The disclosure, including anyreadily discernible variants of the teachings herein, defines, in part,the scope of the foregoing claim terminology such that no inventivesubject matter is dedicated to the public.

1-13. (canceled)
 14. A method for solar generation of a thermoelectricpower output, comprising: positioning an air conduit underground to forman underground conduit, heating a hot side of a thermoelectric generatorhaving a cold side and the hot side via concentrated light rayscollected from a heating system having a solar concentrator andtransported via a fiber optic cable from the solar concentrator to thethermoelectric generator; wherein the solar concentrator includes aplurality of parabolic reflectors oriented to reflect solar energy ontothe fiber optic cable; cooling the cold side of the thermoelectricgenerator via a cooling system; and generating a current from thethermoelectric generator based on a temperature differential between thecold side and the hot side of the thermoelectric generator; passing thecurrent to a transformer to provide an AC current, wherein the coolingsystem includes: a cold side module configured to hold a predeterminedvolume of air, the cold side module having an inlet and an outlet, asubterranean heat exchanger including the underground conduit, theunderground conduit having a first end configured to receive ambient airand a second end coupled to the inlet of the cold side module, and anair exhaust coupled to the outlet of the cold side module and having oneor more valves configured to control an airflow from the subterraneanheat exchanger towards the air exhaust, wherein the heating systemincludes: a hot side module having a first rectangular cuboid shapedefining a first enclosed space, wherein one side of the firstrectangular cuboid shape is defined by the hot side surface of thethermoelectric generator, wherein the hot side module has a hot side airinlet located at a bottom side of the first rectangular cuboid shape anda hot side air outlet located at a top side of the first rectangularcuboid shape.
 15. The method of claim 14, wherein the ambient air has atemperature in a range of 5 to 10° C.
 16. (canceled)
 17. The method ofclaim 14, wherein the cold side module has a rectangular second cuboidshape defining a second enclosed space configured to hold thepredetermined volume of air, wherein the cold side inlet is located at abottom side of the second rectangular cuboid shape and the cold sideoutlet is located at a top side of the second rectangular cuboid shape.18. The method of claim 14, wherein the underground conduit of thesubterranean heat exchanger is a pipe having a plurality of fins. 19.The method of claim 14, wherein the fiber optic cable has a collectionend and a transport end, and the collection end has a collection surfaceangled at 45°.